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Topics - pocock

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Mod Zone / is Talos II overclocking the fan?
« on: October 08, 2020, 04:42:59 pm »

ipmitool tells me that the PWM fan I put in the rear of my case is running at 1800 RPM

Noctua rates it for 1500 RPM +/- 10%, that suggests that 1650 RPM is the maximum

PWM, by definition, can't overclock or overvoltage anything, it simply increases the pulse width up to the point where pulses are 100%.  You can't PWM over 100%

Is the fan simply running outside the spec or could this be a reporting error?

GPU Compute / Accelerators / Sapphire Pulse Radeon RX 550 4GB
« on: October 08, 2020, 03:20:49 pm »
The RX 580 was running fine but I don't use a lot of GPU so I decided to swap it for the Sapphire Pulse Radeon RX 550 4GB, it is half the price.

This card appears to be running fine too.

Monitoring it with the radeontop utility, I'm using 2.5GB of VRAM while driving two screens, one is 4K and the other is 1920x1200

As it is really cheap, I think this card is useful as a spare or for people who don't use GPU-intensive workloads.

The card is less than 2 PCIe slots width so it is an interesting choice for people who are using both slots on a Blackbird.

The sensors command tells me the fan is running at 1231 RPM idle, it is a bit faster than the fans on the RX 580.  I feel it may make just a little bit more noise compared to an idle RX 580 which has two fans that appear to be bigger and quieter.

I may decide to return this one as well and swap it for the Big Navi in November or maybe I will get a Big Navi and keep this as a spare.

My only real concern then is the fan noise, some people may want to pay that little bit more to get a more silent alternative.

A lot of interesting things depend on QtWebEngine

QtWebEngine depends on Chromium, they periodically take a snapshot of the Chromium code from Google

Chromium patching is already in progress, is it complete?

I opened a bug for it within QtWebEngine

When somebody confirms the Chrome patches are ready, the QtWebEngine developers could enable it in their list of supported platforms.  They will probably need to know the minimum supported version of the Chromium code, they probably won't have time to look through the Chromium history, if anybody could add comments to the Qt bug report that would be really helpful.

If they can cherry-pick patches that haven't been accepted by Google, please also comment on that Qt bug report

Talos II / quiet rack mount cases e.g. water cooled or 5U, 140mm fans
« on: October 05, 2020, 11:41:38 am »
I've had a few discussions with people about Talos II and Talos II Lite, mainly based on the recommendations in my recent blog post

One topic that comes up is that some people are space conscious and while the Fractal case is really nice and easy to use for this platform, you need to be able to access it from both sides because the HDDs / SSDs are under the motherboard and any case for the Talos II is going to be big anyway.

One of the ideas emerging from these discussions is building a small rack that can be positioned in the home or office like a chest of drawers or coffee table.  For example, such a rack could be shared between some engineers on a support desk.  A decent UPS can go in the bottom and the Talos II mounted in a large 5U case.  PDUs, network switches, etc can all be mounted on a shelf or rack mounted.  As it is not for data center, 4U to 6U for the workstation chassis is quite acceptable.

As it would combine well with other components, like a rack UPS, it suddenly starts to help save space rather than using more space.

Has anybody had experience with any server chassis between 4U - 6U that has large 140mm quiet fans and accepts regular fanless PSU?

Even if it is not so big, has anybody had any experience making a rack case operate quietly with water cooling?

Operating Systems and Porting / any test servers for developer access?
« on: September 30, 2020, 02:27:56 pm »

I've been discussing a rendering bug with the Blender developers

I suspect the most efficient way for them to investigate would be having their own hardware but if that is not possible, remote access to a demo workstation at Raptor or any other user who has a spare Talos II or Blackbird right now.

Is there anybody who can help out in cases like this?

The vast majority of things I tried are working fine though.  This Blender bug is one of the few cases where something did not work.

Talos II / CPU alignment / slots not working
« on: September 15, 2020, 03:12:48 pm »

After my success with the NVIDIA card, I decided to try it in each slot

I found that it wouldn't work in slot 3, that is the middle 16x slot.

I tried removing and re-inserting it a couple of times and I inspected the slot with a torch and couldn't see any problem

Next I tried removing and re-seating CPU #2.  After doing this, the NVIDIA card in slot 3 is working.

Are there any diagnostics to confirm CPUs are correctly inserted?  Everything else I did on the CPU appeared normal, for example, I had exercised all cores and RAM without problems.

Is there any technique to follow when inserting the CPUs to avoid issues like this?

Operating Systems and Porting / kernel config: page size 4k vs 64k
« on: September 14, 2020, 05:19:55 am »
Most distributions have chosen the 4k page size for their kernels on Intel architectures.

On powerpc64le, Debian (since 2014) and Fedora are using 64k

This may be good for HPC environments but troublesome for workstation users

Here are some specific observations:

Nouveau driver apparaently won't work at all on anything other than 4k

btrfs filesystems have a sectorsize that corresponds to the page size on the host where the filesystem was created.  The filesystems can't be mounted on any host with a different page size.

Example problems:

  • you have a 6TB drive with btrfs from an x86 workstation, you want to move it to a Blackbird running the default Debian or Fedora kernel but it won't mount.
  • you install Fedora 33 with the default kernel (64k page size) and default filesystem (btrfs from Fedora 33) and later you want to recompile your kernel for 4k.  Now you can't mount your root filesystem because mkfs was run for 64k

As Fedora is going to use btrfs by default now, btrfs volumes will be more common and users are more likely to encounter frustration from time to time.

The btrfs developers recently started a patch that allows the systems with 64k page size to read a btrfs volume with 4k sectorsize.  It only works in one direction and it is read-only.

Does anybody feel that distributions should offer different permutations of their kernel and installer based on the 4k page size?

From the perspective of workstation users, are there any other strong reasons, other than Nouveau and btrfs, for distributions to consider this?

Talos II / power consumption observations
« on: September 12, 2020, 01:48:31 pm »

I made the following observations using the meter in my UPS, it measures units of approximately 0.1A

Measurements were made with Debian buster in the idle state, at the GNOME login screen.  It actually uses less power there than at the petitboot menu.

Voltage = 240V

Unplugged: 0

BMC powered: ~ 0.1A

Single 8 core CPU installed with 4 memory chips: add 0.3A - 0.4A above the BMC power draw (total, 0.4A = 96W)

Second 8 core CPU installed with 4 more memory chips: add 0.2A - 0.3A above the single 8 core (total, 0.6A = 144W)

These are bare minimum figures in an idle system with RX 580, LSI 9207-4i4e and one SATA SSD

The system doesn't have the SAS option on the board, that would use more watts if present.

HP suggests a comparable single CPU Z8 G4 workstations can use 74W at idle: (page 31)

Their Z4 workstations can go down to about 40W at idle although the spec is more like a Blackbird with 4 core:

I feel that for people who are mostly idle and just need an occasional boost of power to compile something from time to time, it may be better to stay on a single CPU and Talos II Lite but for people who need the power regularly for different types of work, the HP and Talos II would end up using similar amounts of power.

For people who leave their workstation on all the time or use it as a file server, the second CPU is wasting a lot of power when idle.  As discussed in another thread, it would be useful to have options to power down some cores

Operating Systems and Porting / petitboot doesn't show the OpenBSD partition
« on: September 11, 2020, 01:52:36 pm »

To workaround the issue with my HBA, I removed the HBA and did an install to an SSD in a USB 3 dock (Sharkoon)

The OpenBSD installer completed successfully

petitboot doesn't show the OpenBSD partition in the boot menu

If I exit to the OpenBSD shell, I can use fdisk to inspect the SSD and I can see the partition is there.  It is /dev/sda4 and type = a6 (OpenBSD)

Is there any way I can get petitboot to boot this partition or does it need some newer version of petitboot or some change in the OpenBSD partitioning scheme?

General Discussion / U.2 vs U.3 disks, PCIe 4.0 HBAs
« on: September 07, 2020, 12:29:18 pm »

I was thinking about putting U.2 disks in my workstation to get optimum speed.  However, reading about the subject, I found a few gotchas:

The U.2 disks will not work in future U.3 slots, but U.3 drives will work on U.2 controllers, according to this article.  That is despite all the effort for interoperability promised by tri-mode HBAs.  The implication is that it is better to avoid U.2 now and wait for more U.3 products in the months ahead.

Supermicro's HBA list does not include any PCIe 4.0 product now, using only 50% of the speed of the slots in Talos II.  The PCIe 4.0 cards appear to be arriving in the market very slowly.

It seems that the PCIe 4.0 products that do exist now are not fully supported yet on every OS, e.g. the LSI 9500-8i

For people running Fedora, they will go with Btrfs as the default filesystem soon.  As far as I know, Btrfs mirrored configurations require two copies of each write to go through the bus from CPU to HBA, compared to mirroring in hardware RAID, where the OS only has to send a single write to the RAID controller.  This appears to be another good reason to have the fastest possible storage path, PCIe 4.0

The conclusion: I can live with SATA SSDs running on my LSI 9207-4i4e for 6-12 months while the U.3 drives and PCIe 4.0 Tri-mode controllers become more certain.


According to the PPC page on the OpenBSD web site, OpenBSD 6.8, which is imminent, will be the first official release to support PPC64

Has anybody else tried their PPC64 installer snapshots recently?

After my attempt to run it last week, they included a patch to support machines with larger amounts of memory and the installer progresses further but it still has a limit somewhere.

The next problem I found was that it becomes stuck when I have the LSI 9207-4i4e HBA in the machine.  If I remove the HBA, the OpenBSD installer boots all the way to the first question:

Code: [Select]
Welcome to the OpenBSD/powerpc64 6.8 installation program.
(I)nstall, (U)pgrade, (A)utoinstall or (S)hell?

If anybody else has time to test it, especially if you have accessories like a HBA or NIC, that can help the OpenBSD 6.8 release gain traction or at least help qualify the list of supported hardware on the wiki.

Firmware / swapping flash chips, ordering spares
« on: September 06, 2020, 03:43:52 am »

I looked at the wiki pages Updating Firmware and Debricking the BMC

The latter suggests "Remove the BMC SPI flash chip and reflash it with a flash programmer"

Rather than reflashing the existing chip, it may be safer to keep one additional flash chip on site.  Any new images can be flashed to the spare flash chip, it is swapped into the socket and if it doesn't work, the old chip is swapped back in.

Can anybody clarify the exact type of chip to order?  Are both flash chips identical or different part numbers?

Has anybody seen any useful video that shows the correct way to remove the chip?

I have a CH341A flash programmer, what type of cable or adapter is needed to insert the flash chip, or does it fit directly into one of these programmers?

Operating Systems and Porting / testing a new machine, memory test, etc
« on: September 05, 2020, 02:53:07 pm »

What burn-in test routines do people use when making a new machine or modifying the machine substantially?

For example, on x86 machines, I frequently run memtest86 from a USB stick before installing the OS.  It is not available for OpenPOWER.  It would be really useful to have something like this accessible in petitboot.

Operating Systems and Porting / installers not booting
« on: September 04, 2020, 09:22:43 am »

petitboot starts up and displays the menu

I've tried both the Debian 10 and OpenBSD USB sticks.  Neither of them appears to be working.  The install options (e.g. Debian/Expert mode) appear in petitboot, I select the option I want, the screen goes blank and then displays the message "SIGTERM received, booting..."

Leaving the machine like this for 5 or 10 minutes, nothing more happens, it just appears stuck like that.


Before putting my Talos II into proper use, I might spend a week or so testing different operating systems on it.

Can anybody make any suggestions about things that might be worthwhile to explore?

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